perf(eve): wrap long lines in linear time in the dev TUI by chadhietala · Pull Request #1442 · vercel/eve

chadhietala · 2026-07-31T03:11:20Z

Stacked on #1433 — base is research/subagent-trace-lineage, review that first. First layer of the /traces viewer stack, but standalone: it fixes a module the whole dev TUI already renders through.

wrapVisibleLine word-wrapped by repeatedly measuring and slicing the remaining string — every emitted row re-ran full grapheme segmentation over everything left, so wrapping was quadratic in the line length. Nobody noticed while lines were chat-sized. A single 32 KiB unbroken tool payload (the kind the viewer up-stack renders constantly) cost ~330 ms per wrap, and since the viewer re-renders every card on every keystroke, one big card froze the whole screen.

What changed

The line is tokenized into terminal text units once, and the wrap loop walks them with a cursor (unit index, char offset, remaining visible width). sliceVisible is refactored over a shared sliceUnits so the break-point search reuses the same walk. Semantics are unchanged: break on the last space that fits, hard-cut unbreakable runs, trim the break whitespace, never split inside an ANSI escape, absorb trailing escapes into the slice. One deliberate divergence: break offsets are now always unit-aligned, so an ANSI sequence that happens to contain a space byte can no longer be split mid-sequence (the old code could).

Measured on a real trace with a 32 KiB websearch payload: 330 ms → 8.7 ms collapsed / 15 ms expanded per card, ~700 ms → ~8.5 ms per full viewer frame.

Verification

New tests pin the word-wrap semantics (break-on-last-space, whitespace collapse, hard cuts) and the complexity shape (a 64 KiB unbreakable line wraps in bounded time and reassembles losslessly). pnpm fmt && pnpm lint && pnpm typecheck plus the terminal-text unit suite at this layer; the full sweep (5,707 unit / 575 integration / TUI smoke) ran at the stack top.

wrapVisibleLine re-measured the whole remaining string for every emitted row, so one 32KiB unbroken tool payload cost ~330ms per card render — every keystroke in /traces re-renders every card, making large-payload traces feel frozen. Tokenize once and walk the units with a cursor (~40x faster on real websearch traces). Signed-off-by: Chad Hietala <chadhietala@gmail.com>

vercel · 2026-07-31T03:11:24Z

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Project	Deployment	Actions	Updated (UTC)
eve-docs	Ready	Preview	Jul 31, 2026 3:12am
eve-docs-4759	Ready	Preview, v0	Jul 31, 2026 3:12am

github-actions · 2026-07-31T03:14:49Z

Bundle + Package Summary: `apps/fixtures/weather-agent`

Key takeaways

No notable deltas vs research/subagent-trace-lineage (b34d074).

Delta vs `research/subagent-trace-lineage (b34d074)`

Area	Metric	Baseline	Current	Delta
Package	Packed tarball	7.63 MB	7.63 MB	+1.0 kB ⚠️
Package	Unpacked publish size	28.80 MB	28.80 MB	+472 B ⚠️
Package	Installed footprint	91.31 MB	91.31 MB	+472 B ⚠️
Package	Published files	2872	2872	0
Package	Installed files	6665	6665	0
Runtime	Unique function payloads	2	2	0
Runtime	Total function bytes	16.82 MB	16.82 MB	-40 B ✅
Runtime	Public routes	11	11	0

Changed function payloads vs research/subagent-trace-lineage (b34d074) (2)

Function	Status	Baseline	Current	Delta	Route changes
`functions/__server.func`	changed	8.41 MB	8.41 MB	-20 B ✅	none
`functions/.well-known/workflow/v1/flow.func`	changed	8.41 MB	8.41 MB	-20 B ✅	none

`eve init` install

Metric	Baseline	Current	Delta
Installed footprint	129.71 MB	129.71 MB	+472 B ⚠️
Installed packages	128	128	0
dependencies	4	4	0
devDependencies	2	2	0
Dependency package bytes	43.17 MB	43.17 MB	+472 B ⚠️
devDependency package bytes	5.04 MB	5.04 MB	0 B ➖

Build Metadata

Preset: vercel
Nitro: nitro@3.0.260610-beta
Output directory: apps/fixtures/weather-agent/.vercel/output
Build metadata timestamp: 2026-07-31T03:14:02.178Z
Route aliases: 11 public, 1 internal (12 total aliases)
Vercel routes in config: 14
Severity legend: 🔴 dominant/large, 🟠 notable, 🟡 watch, ⚪ small

Package Drill-Down

Package Details

Package: eve@0.29.2
Package directory: packages/eve
Tarball: 7.63 MB (eve-0.29.2.tgz)
Unpacked payload: 28.80 MB across 2872 published files
Installed footprint: 91.31 MB across 6665 installed files
Installed root package: 27.45 MB
Installed dependencies: 63.86 MB
Runtime dependencies: 2
Peer dependencies: 5 (4 optional)

Installed footprint is measured from an isolated temporary npm install of the packed tarball.

Heavy installed dependencies

eve: 27.45 MB (30.1%)
@rolldown/binding-linux-x64-gnu: 19.28 MB (21.1%)
@rolldown/binding-wasm32-wasi: 10.66 MB (11.7%)
@napi-rs/wasm-runtime: 6.56 MB (7.2%)
ai: 6.56 MB (7.2%)

Publish payload breakdown

Published file size
🔴 dist/src/compiled/shadcn-registry/index.js       [########################] 13.15 MB 45.7%
🟠 dist/src/compiled/experimental-ai-sdk-code-mo... [###.....................] 1.51 MB 5.2%
🟡 dist/src/compiled/@vercel/sandbox/index.js       [#.......................] 632.5 kB 2.2%
🟡 dist/src/compiled/_chunks/workflow/undici-DWL... [#.......................] 502.4 kB 1.7%
🟡 dist/src/compiled/@chat-adapter/slack/index.js   [#.......................] 440.5 kB 1.5%
🔴 Other published files                            [#######################.] 12.57 MB 43.6%

Installed footprint breakdown

Installed package size
🔴 eve                             [########################] 27.45 MB 30.1%
🔴 @rolldown/binding-linux-x64-gnu [#################.......] 19.28 MB 21.1%
🔴 @rolldown/binding-wasm32-wasi   [#########...............] 10.66 MB 11.7%
🔴 @napi-rs/wasm-runtime           [######..................] 6.56 MB 7.2%
🔴 ai                              [######..................] 6.56 MB 7.2%
🔴 zod                             [####....................] 5.07 MB 5.5%
🔴 Other installed packages        [##############..........] 15.73 MB 17.2%

Runtime dependencies (2)

Package	Range	Notes
`nitro`	`3.0.260610-beta`
`undici`	`8.9.0`

Peer dependencies (5)

Package	Range	Notes
`@opentelemetry/api`	`^1.0.0`	optional peer
`ai`	`catalog:`
`braintrust`	`^3.0.0`	optional peer
`just-bash`	`^3.0.0`	optional peer
`microsandbox`	`^0.5.0`	optional peer

eve init install drill-down

`eve init` install details

Command: eve init my-agent
Package manager: npm
Installed footprint: 129.71 MB across 8533 installed files
Installed packages: 128 total (122 transitive-only)
dependencies: 4 direct packages totaling 43.17 MB
devDependencies: 2 direct packages totaling 5.04 MB
Other transitive package files: 81.50 MB

Installed footprint is measured from an isolated temporary eve init my-agent using the current packed eve tarball.

Heavy installed dependencies

@typescript/typescript-linux-x64: 27.95 MB (21.5%)
eve: 27.45 MB (21.2%)
@rolldown/binding-linux-x64-gnu: 19.28 MB (14.9%)
@rolldown/binding-wasm32-wasi: 10.66 MB (8.2%)
zod: 9.02 MB (7.0%)

Installed footprint breakdown

Installed package size
🔴 @typescript/typescript-linux-x64 [########################] 27.95 MB 21.5%
🔴 eve                              [########################] 27.45 MB 21.2%
🔴 @rolldown/binding-linux-x64-gnu  [#################.......] 19.28 MB 14.9%
🔴 @rolldown/binding-wasm32-wasi    [#########...............] 10.66 MB 8.2%
🔴 zod                              [########................] 9.02 MB 7.0%
🔴 @napi-rs/wasm-runtime            [######..................] 6.56 MB 5.1%
🔴 ai                               [######..................] 6.56 MB 5.1%
🔴 Other installed packages         [###################.....] 22.23 MB 17.1%

dependencies (4)

Package	Range	Installed size	Share
`@vercel/connect`	`0.4.2`	135.8 kB	0.1%
`ai`	`^7.0.38`	6.56 MB	5.1%
`eve`	`file:eve-0.29.2.tgz`	27.45 MB	21.2%
`zod`	`4.4.3`	9.02 MB	7.0%

devDependencies (2)

Package	Range	Installed size	Share
`@types/node`	`24.x`	2.54 MB	2.0%
`typescript`	`7.0.2`	2.50 MB	1.9%

Function Drill-Down

Payload Size Graph

Unique function payload size and share of total
🔴 functions/.well-known/workflow/v1/flow.func     [########################] 8.41 MB 50.0%
🔴 functions/__server.func                         [########################] 8.41 MB 50.0%

Top Function Payloads

🟠 functions/.well-known/workflow/v1/flow.func • 1 public route • 8.41 MB

Metric	Value
Public routes	`/.well-known/workflow/v1/flow`
Runtime	`nodejs24.x`
Handler	`index.mjs`
Payload	8.41 MB
Function files	8.41 MB across 43 files
Traced dependencies	0 B
Signal	🟠 Bundled file `index.mjs` is 2.31 MB (27.5%)

🟠 🔎 Dependency Analysis

📦 Bundled files:

Bundled file size
🟠 index.mjs                       [########################] 2.31 MB 27.5%
🟠 _chunks/runtime-artifacts.mjs   [################........] 1.59 MB 18.9%
🟡 _libs/undici.mjs                [##########..............] 980.5 kB 11.7%
🟡 _chunks/sandbox.mjs             [########................] 768.8 kB 9.1%
🟡 _libs/@ai-sdk/gateway+[...].mjs [####....................] 432.8 kB 5.1%
🟠 Other bundled files             [########################] 2.32 MB 27.6%

🧾 Vercel Config

{
  "handler": "index.mjs",
  "launcherType": "Nodejs",
  "shouldAddHelpers": false,
  "supportsResponseStreaming": true,
  "runtime": "nodejs24.x",
  "maxDuration": "max",
  "experimentalTriggers": [
    {
      "type": "queue/v2beta",
      "topic": "__eve776561746865722d6167656e74_wkf_workflow_*",
      "consumer": "default",
      "retryAfterSeconds": 5,
      "initialDelaySeconds": 0
    }
  ],
  "environment": {
    "WORKFLOW_PRECONDITION_GUARD": "1"
  }
}

🟠 functions/__server.func • 10 public routes, 1 internal alias • 8.41 MB

Metric	Value
Public routes	`/` `/eve/v1/callback/[token]` `/eve/v1/connections/[name]/callback/[token]` `/eve/v1/health` `/eve/v1/info` `/eve/v1/session` `/eve/v1/session/[sessionId]` `/eve/v1/session/[sessionId]/cancel` `/eve/v1/session/[sessionId]/stream` `/eve/v1/session/reset`
Internal aliases	`/__server`
Runtime	`nodejs24.x`
Handler	`index.mjs`
Payload	8.41 MB
Function files	8.41 MB across 43 files
Traced dependencies	0 B
Signal	🟠 Bundled file `index.mjs` is 2.31 MB (27.5%)

🟠 🔎 Dependency Analysis

📦 Bundled files:

Bundled file size
🟠 index.mjs                       [########################] 2.31 MB 27.5%
🟠 _chunks/runtime-artifacts.mjs   [################........] 1.59 MB 18.9%
🟡 _libs/undici.mjs                [##########..............] 980.5 kB 11.7%
🟡 _chunks/sandbox.mjs             [########................] 768.8 kB 9.1%
🟡 _libs/@ai-sdk/gateway+[...].mjs [####....................] 432.8 kB 5.1%
🟠 Other bundled files             [########################] 2.32 MB 27.6%

🧾 Vercel Config

{
  "handler": "index.mjs",
  "launcherType": "Nodejs",
  "shouldAddHelpers": false,
  "supportsResponseStreaming": true,
  "runtime": "nodejs24.x"
}

Build Timing: `e2e/fixtures/agent-tools-sandbox`

This is an informational timing measurement inside eve build, from preflight through publication. Output-size measurement and profile writing are excluded.

Build mode: deployable Vercel build with sandbox template prewarm included.

Build pipeline: 2.08 s -> 2.03 s (-43.0 ms) vs research/subagent-trace-lineage (b34d074).
Timing is informational: shared GitHub runners are too variable for a hard timing budget.

Detailed phase timings vs `research/subagent-trace-lineage (b34d074)`

Phase	Baseline	Current	Delta
`extension.check`	13.0 ms	5.1 ms	-7.9 ms
`project.resolve`	1.6 ms	0.9 ms	-0.7 ms
`workspace.create`	1.3 ms	2.4 ms	+1.1 ms
`host.prepare`	248.6 ms	211.7 ms	-36.9 ms
`vercel.service-prefix.resolve`	1.8 ms	1.9 ms	+0.1 ms
`nitro.create`	195.6 ms	194.4 ms	-1.2 ms
`sandbox.prewarm`	299.1 ms	289.8 ms	-9.3 ms
`nitro.cache.prepare`	0.2 ms	0.2 ms	0.0 ms
`nitro.prepare`	0.8 ms	0.8 ms	0.0 ms
`nitro.public-assets`	0.7 ms	0.7 ms	0.0 ms
`nitro.prerender`	0.6 ms	0.4 ms	-0.2 ms
`nitro.bundle`	1.29 s	1.30 s	+14.0 ms
`nitro.cache.write`	0.3 ms	0.3 ms	0.0 ms
`vercel.workflow-function.materialize`	18.5 ms	16.6 ms	-1.9 ms
`agent-summary.emit`	0.5 ms	0.5 ms	0.0 ms
`nitro.close`	0.1 ms	0.1 ms	0.0 ms
`output.publish`	2.9 ms	2.9 ms	0.0 ms
`workspace.remove`	1.7 ms	1.6 ms	-0.1 ms

chadhietala changed the title ~~trace wrap perf~~ Wrap long lines in linear time in the dev TUI Jul 31, 2026

chadhietala mentioned this pull request Jul 31, 2026

feat(eve): add the /traces conversation viewer to the dev TUI #1403

Open

vercel Bot deployed to Preview – eve-docs-4759 July 31, 2026 03:12 View deployment

vercel Bot deployed to Preview – eve-docs July 31, 2026 03:12 View deployment

chadhietala mentioned this pull request Jul 31, 2026

feat(eve): capture model and tool content on local trace spans #1443

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chadhietala changed the title ~~Wrap long lines in linear time in the dev TUI~~ perf(eve): wrap long lines in linear time in the dev TUI Jul 31, 2026

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perf(eve): wrap long lines in linear time in the dev TUI - #1442

perf(eve): wrap long lines in linear time in the dev TUI#1442
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trace-wrap-perf

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Bundle + Package Summary: apps/fixtures/weather-agent

Delta vs research/subagent-trace-lineage (b34d074)

eve init install

Package Details

eve init install details

Payload Size Graph

Top Function Payloads

Build Timing: e2e/fixtures/agent-tools-sandbox

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Bundle + Package Summary: `apps/fixtures/weather-agent`

Delta vs `research/subagent-trace-lineage (b34d074)`

`eve init` install

`eve init` install details

Build Timing: `e2e/fixtures/agent-tools-sandbox`